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/* Licensed under LGPLv2.1+ - see LICENSE file for details */
#ifndef CCAN_CRCSYNC_H
#define CCAN_CRCSYNC_H
#include <stdint.h>
#include <stddef.h>
/**
* crc_of_blocks - calculate the crc of the blocks.
* @data: pointer to the buffer to CRC
* @len: length of the buffer
* @blocksize: CRC of each block (final block may be shorter)
* @crcbits: the number of bits of crc you want (currently 64 maximum)
* @crc: the crcs (array will have (len + blocksize-1)/blocksize entries).
*
* Calculates the CRC of each block, and output the lower @crcbits to
* @crc array.
*/
void crc_of_blocks(const void *data, size_t len, unsigned int blocksize,
unsigned int crcbits, uint64_t crc[]);
/**
* crc_context_new - allocate and initialize state for crc_find_block
* @blocksize: the size of each block
* @crcbits: the bits valid in the CRCs (<= 64)
* @crc: array of block crcs (including final block, if any)
* @num_crcs: number of block crcs
* @tail_size: the size of final partial block, if any (< blocksize).
*
* Returns an allocated pointer to the structure for crc_find_block,
* or NULL. Makes a copy of @crc.
*/
struct crc_context *crc_context_new(size_t blocksize, unsigned crcbits,
const uint64_t crc[], unsigned num_crcs,
size_t final_size);
/**
* crc_read_block - search for block matches in the buffer.
* @ctx: struct crc_context from crc_context_new.
* @result: unmatched bytecount, or crc which matched.
* @buf: pointer to bytes
* @buflen: length of buffer
*
* Returns the number of bytes of the buffer which have been digested,
* and sets @result either to a negagive number (== -crc_number - 1)
* to show that a block matched a crc, or zero or more to represent a
* length of unmatched data.
*
* Note that multiple lengths of unmatched data might be returned in a row:
* you'll probably want to merge them yourself.
*/
size_t crc_read_block(struct crc_context *ctx, long *result,
const void *buf, size_t buflen);
/**
* crc_read_flush - flush any remaining data from crc_read_block.
* @ctx: the context passed to crc_read_block.
*
* Matches the final data. This can be used to create a boundary, or
* simply flush the final data. Keep calling it until it returns 0.
*/
long crc_read_flush(struct crc_context *ctx);
/**
* crc_context_free - free a context returned from crc_context_new.
* @ctx: the context returned from crc_context_new, or NULL.
*/
void crc_context_free(struct crc_context *ctx);
#endif /* CCAN_CRCSYNC_H */
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